In downlink transmission in a long term evolution (LTE) Rel-8/9/10 communication system, an evolved base station (eNB for short) transmits a physical downlink shared channel (PDSCH) and a corresponding physical downlink control channel (PDCCH) to each scheduled user equipment according to a scheduling result.
The PDCCH is used to transmit scheduling indication signaling for uplink or downlink data transmission of a user, where the scheduling indication signaling includes: resource allocation of a data channel, a modulation and coding scheme, and so on. Each PDCCH is made up of 1/2/4/8 control channel elements (CCE), respectively corresponding to different encoding rates. Each CCE is mapped to a group of specific time-frequency REs (RE) in a PDCCH region.
In a further evolution of an LTE Rel-10 system, multiple user multiple input multiple output (MU MIMO) and multi-cell coordination need to be supported to improve system performance, and the number of simultaneously scheduled user equipments is increased by these technologies; however, the capacity of the PDCCH is limited, which limits the number of user equipments that can be scheduled by a base station. Therefore, the prior art enhances the PDCCH, that is, divides a part of resources from an original physical downlink shared channel (PDSCH) region, for transmitting an extended PDCCH, Extended-Physical Downlink Control Channel (E-PDCCH), thereby increasing the capacity of the PDCCH and the number of simultaneously scheduled user equipments.
Because the introduced E-PDCCH needs to satisfy system configuration and user configuration requirements that change continuously in transmission and reception processes, an Extended-Control Channel Element, extended control channel element (E-CCE) that carries the E-PDCCH is required to keep changing semi-statically or dynamically. However, the E-CCE in the prior art is fixed, and a transmission problem of available changing transmission resources caused by introduction of the E-PDCCH cannot be solved. Therefore, the prior art has problems of low transmission efficiency and too high transmission complexity in transmission involving the E-PDCCH.